Self-feeding double-cut saw

ABSTRACT

This invention relates to a saw for cutting a plurality of work pieces to the same length that is characterized by a pair of dogcarrying roller chains, one of which runs in fixed position on a headstock subassembly while the other runs parallel thereto on a transversely-adjustable tailstock subassembly. These chains cooperate with one another to carry the work pieces one at a time into the cutting area and they run in synchronized relationship because of a common drive shaft which can be driven at different speeds to vary the feed rate. One saw forms a part of the headstock subassembly while the other is a part of the tailstock subassembly and is, therefore, movable therewith. The saws are mounted in transversely-spaced parallel relation to one another about a common horizontal axis of rotation while one feed chain is longitudinally adjustable relative to the other so that the work pieces will move into the blades simultaneously in perpendicular relation to the planes defined thereby.

United States Patent 1 Junk et al.

[ SELF-FEEDING DOUBLE-CUT SAW [75] Inventors: Thomas A. Junk; Carl P.Junk, both I of Colorado Springs, C010.

[73] Assigneef Component Equipment Manufacturing, Inc., ColoradoSprings, C010.

22 Filed: Dec.22, 1970 I 21 Appl. No.: 100,668

[52] US. Cl 83/423, 83/4252, 83/433,

83/4352 [51] Int. Cl B27b 25/04, B27b 7/04, B26d 7/06 [58] Field ofSearch 173/36, 37, 37 A,

[111 3,745,866 [451 July 17,1973

Primary Examiner-Donald R. Schran Attorney-Anderson, Spangler & Wymore[57] ABSTRACT This invention relates to a saw for cutting a plurality ofwork pieces to the same length that is characterized by a pair ofdog-carrying roller chains, one of which runs in fixed position on aheadstock subassembly while the other runs parallel thereto on atransversely-adjustable tailstock subassembly. These chains cooperatewith one another to carry the work pieces one at a time into the cuttingarea and they run in synchronized relationship because of a common driveshaft which can be driven at different speeds to vary the feed rate. Onesaw forms a part of the headstock subassembly while the other is a partof the tailstock subassembly and is, therefore, movable therewith. Thesaws are mounted in transversely-spaced parallel relation to one anotherabout a common horizontal axis of rotation while one feed chain islongitudinally adjustable relative to the other so that the work pieceswill move into the blades simultaneously in perpendicular relation tothe planes defined thereby.

5 Claims, 12 Drawing Figures THOMAS A. JUNK CARL P JUNK INVENTORS TO EYS PATENTED 3.745.866

SHEEI 2 0F 5 rsom THOMAS A JUNK CARL F. JUNK PAIENIEDJULWW 3.745.866

THOMAS A. JUNK CARL P JUNK INYENTORS RNEQ PATENIEU Jill 7 SHEU 5 OF 5 T0EYS CARL P JUNK INVENTORS THOMAS A. JUNK SELF-FEEDING DOUBLE-CUT SAWLumber mills, building contractors and even many lumber yards have arecurrent need for a double-cut saw that will square-cut both ends of apiece of dimensionlumber simultaneously, do so rapidly, and providemeans for varying the length of the work piece easily and accurately.Such a unit becomes especially useful when cutting a number of workpieces the same length such as, for example, wall studs. Also, it wouldbe highly desirable to have such a unit provided with its ownself-feeding mechanism automatically operable to orient the work piecesrelative to the saw blades and push them therethrough.

It has now been found in accordance with the teaching of the instantinvention that a double-cut saw of the type aforementioned can be madewith a pair of electric-motor-driven circular saws mounted intransversely-spaced parallel relation to one another for rotation abouta common horizontal axis. The saw blades are independently driven butmounted in subassemblies that are movable relative to one another so asto vary the spacing therebetween. The two circular saws are kept in aprecise parallel relationship by means of transversely-extendingparallel bedframe members that slidably mount the tailstock subassemblyand the saw that forms a part thereof. Both the head and tailstocksubassemblies also carry guided roller chain loops which parallel oneanother and cooperate to feed the work pieces one at a time into thesaws. These chain loops both carry work piece-feeding lugs and one ofthe chains is longitudinally adjustable relative to the other so thatthe lugs will move in pairs paralleling the common axis of bladerotation when driven synchronously by a commonsprocket drive.

' Accordingly, it is the principal object of the present invention toprovide a novel and improved self-feeding double-cut saw. a

A second objective of the invention herein disclosed and claimed istoprovide a unit of the type aforementioned that has a pair ofdog-carrying roller chain conveyors mounted for both longitudinal andtransverse adjustment relative to one another.

Another object is to provide a device for squarecutting both ends of awork piece simultaneously and to a precise, yet adjustable, length.-

Still another objective is the provision of a high capacity self-feedingsaw having a self-aligning feature by means of which the work piece willbe automatically oriented normal to the plane of blade rotation prior toreaching same.

An additional object is to provide a saw of the type forming the subjectmatter hereof that includes a yieldable roller chain drive train thatwill be'overridden automatic'ally in the event a kick-back or jam occurswhen a work piece moves against the blades.

Further objects of the within described invention are to provide adual-bladed high-capacity saw for cutting dimension lumber to lengththat is accurate, safe, versatile, simple to operate, easily adjusted,comparatively inexpensive, lightweight yetrugged, and readily adaptableto various types, grades and sizes of dimension lumber.

Other objects will be in part apparent and in part pointed outspecifically herein in connection with the description of the drawingsthat follows and in which:

FIG. 1 isa perspective view looking down and to the right upon thedouble-cut saw of the present invention;

FIG. 2 is a fragmentary top plan view with both the center section andthe end adjacent the movable tailstock subassembly having been brokenaway to conserve space;

FIG. 3 is a fragmentary rear elevation which, once again, has the centerand one end broken away in the same manner as FIG. 3;

FIG. 4 is a longitudinal section taken along line 4-4 of FIG. 2revealing the details of the movable tailstock subassembly andassociated frame members;

FIG. 5 is a longitudinal section taken along line 5-5 of FIG. 2 showingthe opposite side of the tailstock subassembly;

a FIG. 6 is a fragmentary sectional detail showing the toggle connectorby means of which the tailstock subassembly is held in adjusted positionon the bedframe;

FIG. 7 is an enlarged fragmentary view, half in elevation and half insection and with portions broken away to conserve space, showing thedrive for the dog carrying roller chain loops;

FIG. 8 is a further enlarged fragmentary detail, por-' tions of whichhave been shown in section on the remainder in elevation, revealing therack-and-pinion drive for the tailstock subassembly;

FIG. 9 is a fragmentary detail to an enlarged scale showing thecircumferentially-adjustable drive sprocket for one of the dog-carryingroller chains, the drive shaft having been shown in section;

FIG. 10 is an enlarged fragmentary detail, certain portions of whichhave been broken away to conserve space andother portions broken away toreveal the interior construction, showing the adjustable support bracketand journal for the dog-chain drive shaft, the latter having beensectioned;

FIG. 11 is an enlarged fragmentary elevation showing a pair of adjacentrollerchain links with the work piecefeeding dog attached therebetween;and, FIG. 12 is a section taken along line 12-42 of FIG. 11.

Referring next to the drawings for a detailed description of the presentinvention and, initially, to FIG. 1 for thispurpose, reference numeral10 has been chosen to designate the double-cut saw in its entirety whilenumerals I2 and 14, similarly refer to the headstock and tailstocksubassemblies, respectively, thereof. Both the headstockand tailstocksubassemblies are mounted on a main bedframe 16, the former being fixedwhile the latter is movable therealong. For purposes of the presentdescription as has been the case thus far, the term longitudinally willrefer to the: direction the work piece moves across the unit during thesawing operation and the tenn transversely" will designate movement in adirection normal to the travel of the work piece. As so construed, thetailstock subassembly 14 moves transversely relative to the fixedheadstock subassembly while the dog-carrying roller chain conveyor loop18? and 18M reaved therein. run longitudinally.

The bedframe 16 has floorstands 20 at opposite ends that areinterconnected by three transversely-extending rails 22F, 22R and 22U,the alphabetical subscripts designating the location thereof in terms offront, rear and underneath, the unit being consideredv as feeding fromthe front where the operator stands to the rear where the cut workpieces are discharged. All three rails, in the particular form shown,are hollow and have square cross sections which are rotated45 so thatthe diagonals rather than the sides thereof are horizontal and vertical,respectively. The two upper rails 22F and 22R are raised above the fioorabout the same distance and are displaced horizontally in parallelrelation to one another while the third rail 22U is located beneath andbetween the latter. Permanently affixed to the lowermost corners of boththe upper rails 22F and 22R are lengths of roller chain 24 that definethe racks with which the sprocket wheel pinions 26 mesh that drive thetailstock subassembly 14 from side to side, all of which will beexplained in somewhat greater detail in connection with FIG. 8. Theupwardly and rearwardlydnclined face of rail 22F carries a scale 28marked at appropriate intervals to indicate the transverse spacingbetween the blades 30P and 30M (FIG. of the head and tail-stocksubassemblies.

Next with reference to FIGS. 1, 2 and 3, it will be seen that theheadstock subassembly 12 contains a fixed subframe generally referred toby numeral 32F and which includes a longitudinally-extending invertedgenerally trapezoidal mounting plate 34?, a horizontally-disposed plate36P attached to the latter that carries saw motor 38?, a similar motormount 40 for the gear motor 42 that drives the square drive shaft 44 ofthe roller chain feed conveyors 18. A shield 46P covers the saw motorand is attached to the mounting plate 36] of the subframe. Thetrapezoidal plate 34P carries a hinged saw blade guard 48P ofconventional design that rests atop the work pieces and holds them downwhile they are being cut. The rear extremity of the trapezoidal subframeplate has a braced extension arm 50F attached thereto that receives thecut work pieces and holds them until they can be removed and stacked.The outside surface of this same plate mounts the stop-start switchesfor the individual saw motors while a bracket 54 attached to the lattercarries conventional SCR speed controller 56 that governs the speed ofthe gear motor 42. i

In the preferred embodiment of the invention illustrated, the fixedsubframe 36P also carries certain appurtenances which, while notabsolutely necessary, improve the unit considerably. The first of theseis fence 58, the longitudinally-extending element 60 of which abuts theleft end of the work piece as it is placed across the roller chain feedconveyors 18. This fence includes a T-bracket, the crossbar 62 of whichis fastened to the outside of subframe mounting plate 34P with the stem64 thereof projecting horizontally and perpendicularly to the left as asupport for element 60. While not specifically illustrated as such, boththe crossbar 62 and the stem 64 of the T-bracket comprise lengths ofunistrut which are detachably connected to one another so that the sternand its associated fence-forming element 60 can be removed from thefixed subframe 32? and remounted as shown in FIGS. 4 and 5 on themovable subframe 32M. For this purpose, a second crossbar 62M isfastened to the righthand face of mounting plate 34M to receive thisfence. Obviously, the fence 58 will be used on either the headstock orthe tailstock but not both; however, there are occasions when oneposition is preferred over the other.

As is the case with most saw fences, they are adjustable so as to varythe length of the severed end. No attempt has been made here to detailthe mounting of the fence-forming element 60 longitudinally on unistrutstem 64 because this is conventional and any one of many different typesof adjustable saw fences will suffice quite well for purposes of theinstant invention.

Another of the elements carried by plate 34? of the subframe 32! on theoutside or left-hand face thereof is a sawdust duct 68P shown in FIG. 1.This duct is placed beneath shield 46P adjacent the downtumed front edge70 thereof and the rear wall is slit vertically to receive the leadingedge of the blade just after the teeth thereof leave the work piece.These teeth carry the sawdust directly into duct 68 and it, in turn,conducts it down and to the left of the machine. A similar duct 68M isprovided on the movable subframe 32M that forms a part of the tailstocksubassembly.

A deflector 72P is located adjacent the trailing edge of the saw bladein position to engage the severed end pieces and get them out of the wayof the ascending saw teeth on the trailing edge of the blade. A similardeflector plate 72M is provided on the right-hand face of the movablesubframes mounting plate 34M as has been most clearly shown in FIG. 5.

Having described the construction of the fixed subframe 32? and theappurtenances mounted on the outside face thereof, it will be well torefer briefly to FIGS 2, 3 and Sand do likewise with the movablesubframe 32M that forms a part of the tailstock subassembly 14 beforelooking at the roller chain conveyors 18 that are mounted on the insidethereof along with certain other elements. Some of the subframe elementstogether with the units carried thereby are but mirror images of thecorresponding parts of the headstock subassembly 12. For instance,trapezoidal mounting plate is but a mirror image of plate 34?.Similarly, shield 46M, saw guard 48M, extension arm 50M, deflector plate72M and saw motor 38M if one considers it must rotate in the oppositedirection to motor 38?, are but mirror images of their counterparts onthe fixed subframe. The mount 36M for the saw motor 38M is, of course,much the same regardless of which subframe it is attached to. Certainelements are missing from the movable tailstock subassembly 14 such asthe gear motor 42 and its mounting bracket 40, the stop-start switches52, and the SCR controller 56. Duct 68M is shown to be of a slightlydifferent shape than duct 68] but its function remains the same. Onlyone gear motor is needed because the roller chain conveyor drive shaft44 is common to both of said conveyors ISP and 18M.

Saw blades 30P and 30M are both mounted on the outside of theirrespective mounting plates 34? and 34M for rotation in closely-spacedrelation to the shields 46. Actually, the horizontal portions 80 ofthese shields define the saw table upon which the ends of the workpieces are supported while the midportions thereof are supported on thefeed conveyors 18.

The work piece conveying mechanisms 18 on the inside surfaces of thesubframe mounting plates 34 of both subassemblies l2 and 14 are mostclearly revealed in FIGS. l-4, l l and 12 to which reference will now bemade. A series of idler sprockets 82F and 82M are journalled forrotation in longitudinal alignment with vertical edge 96 of each dogprojects above the top of subframe plate 34 and engages the trailingedge of the work piece pushing it longitudinally from front to rearacross the top of the bedframe. These dogs 86 are located atequally'spaced intervals and are the same distance apart on both chains.As will be explained presently in connection with FIGS. 7 and 9, one ofthe roller chain drive sprockets 100M is circumferentially adjustablerelative to the other of said drive sprockets 100 so as to place thechain dogs in transverselyaligned pairs adapted to move the work piecesat right angles to the saw blades so as to square-cut the ends thereof.Since only the dogs project above the top edge of the subframe plates34, transversely-aligned pairs thereof will cooperate to align a skewedwork piece prior to its being fed to the saw blades.

Now, the drive for the roller chain conveyors 18M and 18F is mostclearly revealed in FIGS. 7, 9 and to which reference will now be made.The output shaft 102 of the gear motor 42 has the drive element 104mounted thereon of a friction clutch that has been indicated in ageneral way by numeral 106. In the particu lar form illustrated, driveelement 104 has an annular flange 108 that mounts a friction disk 110 onthe face thereof. Projecting through the center of disk 110 is anextemally-threaded tubular hub 112 that is in coaxial relation to theoutput shaft and onto which is screwed a nut l 14 that moves a secondfriction element 1 16 axially toward the first. The latter frictionelement 116 includes a backing plate 118 faced by a friction disk 120.

The driven element of the clutch includes a collar 122 fastened to shaft44 for conjoint rotation therewith, and a generally-rectangularconnector 124 having one vertical wall 126 attached to the collar withthe other vertical wall 128 disposed between the friction disks 110 and120. Walls 126 and 128 are bridged by connecting walls 130 as shown.Wall 128 has a central aperture 132 therein that is slightly larger thanthe outside diameter of the hub so as to loosely receive the latter. Theextent to which nut 114 is tightened determines, of course, how tightlythe driven element 124 is squeezed between the friction disks and,therefore, the yield-point of the clutch.

Shaft 44 is, of course, journalled for rotation in coaxial relation tothe motor shaft 102. One shaft journal 134 is located on the face of anupstanding plate 136 mounted atop cross frame element 138 of therighthand floor stand 20. The other journal 140 is carried on the faceof a similar plate 142 mounted atop the gear motor mounting plate 40..Collars 144 fastened to the square shaft 44 lie adjacent the journalsand retain the shaft against axial movement.

The drive sprocket 100M that lies in the vertical plane of roller chainloop 84F in the headstock subassembly 12 is most clearly revealed inFIGS. 7 and 9 to which reference will now be'made. A flanged collar 146is fastened to the shaft 44 for conjoint rotation therewith in fixedposition intermediate its ends. The flange 148 thereof includes a seriesof angularly-spaced arcuate slots 150 curved about the axis of shaftrotation, three of such slots having been shown in FIG. 9 spaced 120apart. Bolts 152 passing through these slots into the sprocket 100Menable the latter to be adjusted circumferentially relative to shaft 44so as to place the dogs 86 carried by chain 84? in proper transversealignment with its counterpart on the other roller chain 84M. Thus,movement of the work pieces into the saw blades at right angles to theplanes in which they turn is assured so that square-cut ends will beproduced.

Returning again to FIG. 7 by itself, it will be noted that sprocket thatmeshes with the other roller chain loop 84M is not provided with meansfor adjusting it rotarially relative to shaft 44 as was the case withsprocket 100M, but rather, it includes a hub 149 with a square hole 151therethrough that is sized to receive said shaft and slide axiallytherealong.

Bracketing hub 149 on both the right and left ends thereof are a pair ofshaft journals 153 and 154 that are, in turn, fastened by brackets 156and 158 to opposite sides of the mounting plate 34M of the movablesubframe 32M. Thus, as the tailstock subassembly is run to-and-fro alongthe three rails 22, these journals 152 and 154 carry the sprocket 100along the shaft 44 to the same position so that it maintains in verticalcoplanar relation to the idler sprockets 82M and roller chain loop 84Mreaved therearound.

Now, in reasonably short version of the saw, up to say 10 feet long,shaft 44 is adequately supported by journals 134 and at opposite endsthereof along with those (152 and 154) intermediate its ends that movewith the tailstock subassembly 14.. In longer versions of the unit, onthe other hand, it is advisable to further support the unsupportedsections of shaft 44 extending to the right or left or both ways fromthe tailstock depending upon its transverse positi-on. For this purpose,an additional shaft-supporting structure has been provided that isbroadly referred to by reference numeral 160 and which is most clearlyshown in FIGS. 7 and 10 to which reference will now be made. Thisstructure includes an angle iron section 162 having a length somewherearound half the length of the rails 22 that is turned as shown in FIG.10so as to conform with and slide along the top of bottom rail 22U. Thisangle iron is supported in spaced relation to the mating surfaces of therail by Nylon pads 164 located at least on both flanges and at both endsif not therebetween. These pads, of course, support angle iron element162 for slidable movement along the rail 22U.

Upstanding metal brackets 166 are fastened to opposite ends of the angleiron and Nylon cradles 168 with a U-shaped notch 170 in the top edgethereof sized to receive and journal shaft 44 for rotation therein arebolted to the brackets. Now, it is obvious that by sliding thisshaft-supporting structure along the lower rail 22U, the cradles 168 can.be placed in position to support the unsupported sections of shaft 44somewhere between the headstock and tailstock and between the tailstockand right-hand floor stand. With the tailstock located closely adjacentone end or the other, only one of the cradles will be functional but itwill be most important due to the long unsupported length of the shaft.

The next feature of the invention that requires a detailed examinationis that of the mounting of the tailstock subassembly 14 on the rails 22and the mechanism for moving the latter to-and-fro relative to theheadstock, all of which are most clearly disclosed in FIGS. 1-5 and 8 towhich reference will now be made. The mounting plate 34M of subframe 32Mis provided with a pair of longitudinally-spaced square openings 172sized and positioned to loosely receive the upper rails 22F and 22R.Fastened within the upper part of these openings 172 so as to projectonto both sides of mounting plate 34M (see FIGS. 4 and 5) are invertedV-shaped saddles 174 having outtumed ears 176 at their free edges thatcarry pins 178 upon which rollers 180 are rotatably fastened. Since theflanges of the saddles terminate short of the corresponding surfaces ofthe rails 22F and 22R atop which they ride, the rollers engage thelatter and support the tailstock subassembly for rolling engagementtherealong.

A pair of pillow blocks 182 are fastened to the lefthand face of themounting plate 34 or just below and inside the rails 22R and 22F (seeFIG. 4) and they journal the crankshaft 184 that carries thepreviouslymentioned pinion-forming sprockets 26 that mate with theroller chain 24 and cooperate therewith to define the rock-and-piniondrive for moving the tailstock subassembly relative to the headstock. Acrank 186 on the front end of the crankshaft is used by the operator tomake the aforementioned adjustments.

Finally, with reference to FIGS. and 6, the toggle mechanism 188 that isused to releasably lock the tailstock subassembly in adjusted positionwill now be described in connection with FIGS. 5 and 6. A bracket 190having an upstanding flange 192 is fastened atop the front flange of thesaddle 174 that rides along front rail 22F. As illustrated, this bracketis on the right side of the mounting plate 34M because otherwise itwould likely interfere with the operation of the rock-andpinion drivedescribed above. A plate 194 is hingedly attached to the front edge ofthis bracket for movement between the disengaged position shown bybroken lines in FIG. 6 and the engaged position revealed in full linesin which said plate parallels the lower front face of the rail 22F anddefines a brake shoe.

A conventional toggle clamp 196 is fastened to the upstanding flange 192of the bracket in position such that movement of the operating handle198 downwardly will cause toggle link 200 to align itself with thelatter thereby moving center pivot 202 across the straight line defineby pivots 204 and 206 thus moving the actuating arm 208 from its brokenline disengaged position into the solid line engaged position holdinghinged plate 194 in braking contact with rail 22F.

What is claimed is:

1. The double-cut saw which comprises: a transversely elongate bedframeincluding a pair of horizontal rails mounted in longitudinally-spacedparallel relation to one another; a fixed subframe having a firstlongitudinally-extending vertically-disposed mounting plate attached toone end of the bedframe; a movable subframe mounted on the rails forrelative movement toward and away from the fixed subframe, said movablesubframe including a second longitudinallyextending vertically-disposedmounting plate located in transversely-spaced parallel relation to saidfirst mounting plate; first circular saw means including a motor and asaw blade driven thereby mounted on the fixed subframe with a portion ofsaid blade projecting above the first mounting plate in parallelrelation alongside thereof; second circular saw means including a motorand a blade driven thereby mounted on the movable subframe for movementtherewith, the blade of said second circular saw means being mountedalongside said second mounting plate of the latter for rotation intransversely-spaced parallel and coaxial relation to the blade of thefirst circular saw means; and, first and second feed conveyor meanscooperating with one another to feed work pieces one-at-a-time to thefirst and second saw means simultaneously, each of said conveyor meansincluding at least two idler sprockets journalled for rotation inlongitudinally-spaced and aligned relation to one another adjacent thetop edge of one of the first and second mounting plates, atransversely-extending drive shaft journalled for rotation at oppositeends of the bedframe about an axis paralleling the rails thereof, afirst drive sprocket mounted on said drive shaft for rotation therewithin coplanar-relation with the idler sprockets carried by the firstmounting plate, a second drive sprocket mounted on said drive shaft forrotation therewith and for slidable movement therealong, bifurcated yokemeans carried by the movable subframe positioned and adapted to engagethe second drive sprocket on opposite sides thereof and maintain same incoplanar relation to the idler sprockets carried by the second mountingplate in all adjusted positions of the latter, an endless loop of rollerchain reaved about each coplanar set of idler and drive sprockets,tranversely-aligned pairs of dogs mounted on the roller chains formovement along the top edges of the first and second mounting platesprojecting thereabove, drive means operatively connected to the driveshaft for driving both chain loops at the same speed and in a directionto push a work piece laid thereacross ahead of a pair of said dogs intothe first and second saw means, and adjustment means interposed betweenthe drive shaft and one of said first and second drive sprocketsoperative upon actuation to effect relative rotation therebetween so asto enable one series of chain dogs to be brought into transversealignment with the companion series thereof carried by the other chainwhile maintaining a constant tension in the roller chain associated withthe sprocket thus adjusted.

2. The double-cut saw as set forth in claim 1 in which: the adjustablemeans comprises a flanged hub fixedly attached to the shaft and matingin face-toface relation with the drive sprocket operatively associatedtherewith, one of said mating elements carrying at least twoangularly-spaced circumferential slots and the other pin-type fastenerspositioned to enter same, said fasteners and slots cooperating inloosened condition to permit the relative rotational movement and intightened condition to fasten same together for conjoint rotation.

3. The double-cut saw as set forth in claim I in which: the bedframeincludes a third rail located in verticallyspaced parallel relationbeneath the conveyor drive shaft; and, in which shaft-supporting meansis mounted atop the third rail for adjustment in the direction of thelength thereof, said means including at least one upstanding bracketmember bridging the gap between said rail and conveyor drive shaft, andsaid bracket member including a notch in the upper edge thereofpositioned and sized to cradle said shaft and prevent it from sagging. v

4. The double-cut saw as set forth in claim 3 in which:

7 the shaft-supporting means includes an elongate sadportion inbearing-forming relation to said drive shaft. t I 1 t

1. The double-cut saw which comprises: a transversely elongate bedframeincluding a pair of horizontal rails mounted in longitudinally-spacedparallel relation to one another; a fixed subframe having a firstlongitudinally-extending verticallydisposed mounting plate attached toone end of the bedframe; a movable subframe mounted on the rails forrelative movement toward and away from the fixed subframe, said movablesubframe including a second longitudinally-extending vertically-disposedmounting plate located in transversely-spaced parallel relation to saidfirst mounting plate; first circular saw means including a motor and asaw blade driven thereby mounted on the fixed subframe with a portion ofsaid blade projecting above the first mounting plate in parallelrelation alongside thereof; second circular saw means including a motorand a blade driven thereby mounted on the movable subframe for movementtherewith, the blade of said second circular saw means being mountedalongside said second mounting plate of the latter for rotation intransverselyspaced parallel and coaxial relation to the blade of thefirst circular saw means; and, first and second feed conveyor meanscooperating with one another to feed work pieces one-at-a-time to thefirst and second saw means simultaneously, each of said conveyor meansincluding at least two idler sprockets journalled for rotation inlongitudinally-spaced and aligned relation to one another adjacent thetop edge of one of the first and second mounting plates, atransversely-extending drive shaft journalled for rotation at oppositeends of the bedframe about an axis paralleling the rails thereof, afirst drive sprocket mounted on said drive shaft for rotation therewithin coplanar relation with the idler sprockets carried by the firstmounting plate, a second drive sprocket mounted on said drive shaft forrotation therewith and for slidable movement therealong, bifurcated yokemeans carried by the movable subframe positioned and adapted to engagethe second drive sprocket on opposite sides thereof and maintain same incoplanar relation to the idler sprockets carried by the second mountingplate in all adjusted positions of the latter, an endless loop of rollerchain reaved about each coplanar set of idler and drive sprockets,tranversely-aligned pairs of dogs mounted on the roller chains formovement along the top edges of the first and second mounting platesprojecting thereabove, drive means operatively connected to the driveshaft for driving both chain loops at the same speed and in a directionto push a work piece laid thereacross ahead of a pair of said dogs intothe first and second saw means, and adjustment means interposed betweenthe drive shaft and one of said first and second drive sprocketsoperative upon actuation to effect relative rotation therebetween so asto enable one series of chain dogs to be brought into transversealignment with the companion series thereof carried by the other chainwhile maintaining a constant tension in the roller chain associated withthe sprocket thus adjUsted.
 2. The double-cut saw as set forth in claim1 in which: the adjustable means comprises a flanged hub fixedlyattached to the shaft and mating in face-to-face relation with the drivesprocket operatively associated therewith, one of said mating elementscarrying at least two angularly-spaced circumferential slots and theother pin-type fasteners positioned to enter same, said fasteners andslots cooperating in loosened condition to permit the relativerotational movement and in tightened condition to fasten same togetherfor conjoint rotation.
 3. The double-cut saw as set forth in claim 1 inwhich: the bedframe includes a third rail located in vertically-spacedparallel relation beneath the conveyor drive shaft; and, in whichshaft-supporting means is mounted atop the third rail for adjustment inthe direction of the length thereof, said means including at least oneupstanding bracket member bridging the gap between said rail andconveyor drive shaft, and said bracket member including a notch in theupper edge thereof positioned and sized to cradle said shaft and preventit from sagging.
 4. The double-cut saw as set forth in claim 3 in which:the shaft-supporting means includes an elongate saddle-forming elementmounted atop the third rail for slidable movement in the direction ofthe length thereof; and, in which two bracket members are mounted atopthe saddle-forming element in position to bracket the movable subframe.5. The double-cut saw as set forth in claim 3 in which: the conveyordrive shaft has a square cross-section; and, in which the bracket memberincludes a plastic portion in bearing-forming relation to said driveshaft.